Opioid and benzodiazepine tolerance and dependence: application of theory to critical care practice

Concurrent Opioid and Benzodiazepine Utilization Patterns and Predictors Among Community-Dwelling Adults in the United States

OBJECTIVE

Using benzodiazepines and opioids together substantially increases the risk of fatal overdose. Yet, concurrent benzodiazepine and opioid prescribing rates continue to increase amid the opioid overdose epidemic. Therefore, this study sought to identify patterns and predictors associated with self-reported concurrent benzodiazepine and opioid use among community-dwelling adults.

METHODS

This retrospective, cross-sectional study used Medical Expenditure Panel Survey data from 2011, 2013, and 2015. The study population included adults (age ≥18) who did not die during the calendar year. The dependent variable was concurrent benzodiazepine and opioid use, which was identified with Multum Lexicon therapeutic class codes. Multivariable logistic regression analysis was conducted to examine the association of various individual-level factors with concurrent benzodiazepine and opioid use.

RESULTS

The final study sample consisted of 44,808 individuals (unweighted), of which 680 (1.6%) (weighted frequency=7,806,636) reported concurrent benzodiazepine and opioid use. Several individual-level factors were significantly associated with reporting use of this combination. For example, individuals with anxiety were more likely to report using both benzodiazepines and opioids (odds ratio [OR]=9.61, 95% confidence interval [CI]=7.37-12.5), and those with extreme pain levels were more likely to report concurrent use (OR=5.11, 95% CI=2.98-8.78). Other predictors of reporting concurrent benzodiazepine and opioid use were depression, arthritis, region, race-ethnicity, insurance, activities disability, general and mental health status, and smoking status.

CONCLUSIONS

Several individual-level factors were associated with reporting concurrent benzodiazepine and opioid use. Therefore, enhanced educational interventions targeting both clinicians and community-dwelling adults are warranted to minimize use of this high-risk medication combination.

The Impact of Bispectral Index Monitoring on Sedation Administration in Mechanically Ventilated Patients

The aim of this prospective randomised controlled trial was to assess the effectiveness of the Bispectral Index (BIS) monitor in supporting clinical sedation management decisions in mechanically ventilated intensive care unit patients. Fifty adult mechanically ventilated surgical and general intensive care unit patients receiving sedative infusions of morphine and midazolam were randomly allocated to receive BIS monitoring (n=25) or standard sedation management (n=25). In the BIS group, sedation was titrated to maintain a BIS value of greater than 70. In the standard management group, sedative needs were titrated based on subjective assessment and clinical signs.

There was no statistically significant difference in the amount of sedation administered (morphine P =0.67 and midazolam P =0.85). However, there was a statistically significant difference in sedation administration over time. Patients in the BIS group received increasing amounts of sedation over time whilst those in the control group received decreasing amounts of sedation over time. The same inverse relationship existed for both sedative agents (morphine P=0.005, midazolam P=0.03). Duration of mechanical ventilation was comparable in the two groups. We conclude that the use of BIS monitoring did not reduce the amount of sedation used, the length of mechanical ventilation time or the length of ICU stay.

Concurrent Use of Benzodiazepine by Heroin Users-What Are the Prevalence and the Risks Associated with This Pattern of Use?

INTRODUCTION

Polydrug use involving heroin and benzodiazepines is common. The potential risk of additive pharmacological effects may be associated with poorer outcomes in patients who use benzodiazepines together with heroin. The aim of this study was to determine the clinical picture of patients presenting to the emergency department following acute drug toxicity involving heroin and benzodiazepines.

METHODS

Exposure information, clinical data and outcome of acute drug toxicity presentations were collected between 1 October 2013 and 30 September 2014 as part of the European Drug Emergencies Network (Euro-DEN) project. The database was interrogated to identify patients who had taken heroin with or without benzodiazepine(s).

RESULTS

A total of 1345 presentations involving acute heroin toxicity were identified: 492 had used one or more non-heroin/benzodiazepine drug and were not further considered in this study; 662 were lone heroin users and 191 had co-used heroin with one or more benzodiazepines. Co-users were more likely than lone heroin users to have reduced respiratory rate at presentation 12.7 ± 4.9 vs 13.6 ± 4.4 (p = 0.02) and require admission to hospital 18.3 vs 9.8% (p < 0.01). There were no differences in critical care admission rates 3.1 vs 3.9% (p = 0.83) or length of stay 4 h 59 min vs 5 h 32 min (p = 0.23). The 3 most common benzodiazepines were clonazepam, diazepam, and alprazolam. No differences were observed for clinical features between the three benzodiazepines.

CONCLUSION

This study shows that co-use of heroin and benzodiazepines is common, although the overall outcomes between co-users of heroin and benzodiazepines and heroin-only users were similar.

Poly-Drug Use of Prescription Medicine among People with Opioid Use Disorder in China: A Systematic Review and Meta-Analysis

BACKGROUND

Opioid use disorder (OUD) causes substantial public health and social problems worldwide. Poly-drug use is common in people with OUD and increases morbidity and mortality. Investigation of the patterns and characteristics of poly-drug use of prescription medicine among opioid users is needed to develop appropriate prevention and intervention strategies.

OBJECTIVES

To estimate the prevalence of poly-drug use of prescription medicine among people with OUD in China using meta-analysis.

METHODS

We searched relevant epidemiological studies published before February 2017 in English and Chinese databases. The quality of included studies was assessed using the Agency for Healthcare Research and Quality scale. The pooled prevalences of prescription medicine use among people with OUD were estimated.

RESULTS

We included 80 eligible studies in the meta-analysis. The main prescription medicines were benzodiazepines (BZDs) and prescription opioid analgesics. The pooled prevalence of unclassified BZDs and prescription opioids was 40.6% and 23.2%, respectively. Diazepam was the most frequently co-used BZD (32.6%), followed by triazolam (32.1%), and estazolam (9.2%). Tramadol was the most commonly used prescription opioid (27.3%), followed by methadone (16.8%), buprenorphine (12.6%), pethidine (8.9%), morphine (6.5%), dihydroetorphine (3.9%), and codeine-containing cough syrup (3.7%). BZDs were mainly used for self-medication (56.1%), whereas prescription opioids were primarily coused for nonmedical purposes (69.4%).

CONCLUSIONS

The results demonstrate that prescription medicine use is widespread among opioid users in China. There needs to be more consideration of poly-drug use, and early interventions and management strategies are needed to prevent poly-drug use among opioid users in China.

Iatrogenic Opioid Withdrawal in Critically Ill Patients: A Review of Assessment Tools and Management

OBJECTIVE

To (1) provide an overview of the epidemiology, clinical presentation, and risk factors of iatrogenic opioid withdrawal in critically ill patients and (2) conduct a literature review of assessment and management of iatrogenic opioid withdrawal in critically ill patients.

DATA SOURCES

We searched MEDLINE (1946-June 2017), EMBASE (1974-June 2017), and CINAHL (1982-June 2017) with the terms opioid withdrawal, opioid, opiate, critical care, critically ill, assessment tool, scale, taper, weaning, and management. Reference list of identified literature was searched for additional references as well as www.clinicaltrials.gov .

STUDY SELECTION AND DATA EXTRACTION

We restricted articles to those in English and dealing with humans.

DATA SYNTHESIS

We identified 2 validated pediatric critically ill opioid withdrawal assessment tools: (1) Withdrawal Assessment Tool-Version 1 (WAT-1) and (2) Sophia Observation Withdrawal Symptoms Scale (SOS). Neither tool differentiated between opioid and benzodiazepine withdrawal. WAT-1 was evaluated in critically ill adults but not found to be valid. No other adult tool was identified. For management, we identified 5 randomized controlled trials, 2 prospective studies, and 2 systematic reviews. Most studies were small and only 2 studies utilized a validated assessment tool. Enteral methadone, α-2 agonists, and protocolized weaning were studied.

CONCLUSION

We identified 2 validated assessment tools for pediatric intensive care unit patients; no valid tool for adults. Management strategies tested in small trials included methadone, α-2 agonists, and protocolized sedation/weaning. We challenge researchers to create validated tools assessing specifically for opioid withdrawal in critically ill children and adults to direct management.

High enhancer, downer, withdrawal helper: Multifunctional nonmedical benzodiazepine use among young adult opioid users in New York City

BACKGROUND

Benzodiazepines are a widely prescribed psychoactive drug; in the U.S., both medical and nonmedical use of benzodiazepines has increased markedly in the past 15 years. Long-term use can lead to tolerance and dependence, and abrupt withdrawal can cause seizures or other life-threatening symptoms. Benzodiazepines are often used nonmedically in conjunction with other drugs, and with opioids in particular-a combination that can increase the risk for fatal and non-fatal overdose. This mixed-methods study examines nonmedical use of benzodiazepines among young adults in New York City and its relationship with opioid use.

METHODS

For qualitative analysis, 46 90-minute semi-structured interviews were conducted with young adult opioid users (ages 18-32). Interviews were transcribed and coded for key themes. For quantitative analysis, 464 young adult opioid users (ages 18-29) were recruited using Respondent-Driven Sampling and completed structured interviews. Benzodiazepine use was assessed via a self-report questionnaire that included measures related to nonmedical benzodiazepine and opioid use.

RESULTS

Participants reported using benzodiazepines nonmedically for a wide variety of reasons, including: to increase the high of other drugs; to lessen withdrawal symptoms; and to come down from other drugs. Benzodiazepines were described as readily available and cheap. There was a high prevalence (93%) of nonmedical benzodiazepine use among nonmedical opioid users, with 57% reporting regular nonmedical use. In bivariate analyses, drug-related risk behaviours such as polysubstance use, drug binging, heroin injection and overdose were strongly associated with regular nonmedical benzodiazepine use. In multivariate analysis, growing up in a middle-income household (earning between $51,000 and $100,000 annually), lifetime overdose experience, having ever used cocaine regularly, having ever been prescribed benzodiazepines, recent drug binging, and encouraging fellow drug users to use benzodiazepines to cope with opioid withdrawal were consistently strong predictors of regular nonmedical benzodiazepine use.

CONCLUSION

Nonmedical benzodiazepine use may be common among nonmedical opioid users due to its drug-related multi-functionality. Harm reduction messages should account for the multiple functions benzodiazepines serve in a drug-using context, and encourage drug users to tailor their endorsement of benzodiazepines to peers to include safer alternatives.

Tolerance and Withdrawal Issues with Sedatives in the Intensive Care Unit

Prolonged use of sedative medications continues to be a concern for critical care practitioners, with potential adverse effects including tolerance and withdrawal. The amount of sedatives required in critically ill patients can be lessened and tolerance delayed with the use of pain and/or sedation scales to reach the desired effect. The current recommendation for prolonged sedation is to wean patients from the medications over several days to reduce the risk of drug withdrawal. It is important to identify patients at risk for iatrogenic withdrawal and create a treatment strategy.

Effects of dexmedetomidine on procedural pain and discomfort associated with central venous catheter insertion

BACKGROUND AND AIM

Central venous catheter (CVC) insertion induces pain and discomfort to a conscious patient despite application of a local anaesthetic (LA) field block and this pain can be greatly lessened by using additional analgesics. The aim of this study was to evaluate the efficacy of dexmedetomidine along with LA field infiltration in controlling pain and discomfort associated with CVC insertion.

METHODS

A prospective, randomised, double-blind, placebo-controlled trial of 54 patients scheduled for planned CVC insertion was undertaken. Patients were randomly assigned into two groups of 27 each, to receive either dexmedetomidine (1 μg/kg) or 0.9% normal saline, along with LA field infiltration. Pain and discomfort score was measured at 5 time points.

RESULTS

The median pain score was worst for placebo group at local anaesthetic injection (6 [4-7]) and at the end of procedure (5 [4-5]), which was significantly attenuated in the dexmedetomidine group (4 [4-5] and 4 [3-5]; P = 0.007 and 0.040 respectively). The lower procedure related discomfort score in the immediate post-procedural period was statistically significant in dexmedetomidine group compared to placebo (4 [4-5] vs. 5 [4-6]; P = 0.008).

CONCLUSIONS

Pre-procedural bolus dexmedetomidine infusion provides adequate analgesia and patient comfort for CVC insertion along LA field block. However, the tendency for excessive sedation and bradycardia associated with dexmedetomidine render it less desirable for this purpose.

Polydrug abuse: a review of opioid and benzodiazepine combination use

This paper reviews studies examining the pharmacological interactions and epidemiology of the combined use of opioids and benzodiazepines (BZDs). A search of English language publications from 1970 to 2012 was conducted using PubMed and PsycINFO(®). Our search found approximately 200 articles appropriate for inclusion in this paper. While numerous reports indicate that the co-abuse of opioids and BZDs is ubiquitous around the world, the reasons for the co-abuse of these medications are not entirely clear. Though the possibility remains that opioid abusers are using BZDs therapeutically to self-medicate anxiety, mania or insomnia, the data reviewed in this paper suggest that BZD use is primarily recreational. For example, co-users report seeking BZD prescriptions for the purpose of enhancing opioid intoxication or "high," and use doses that exceed the therapeutic range. Since there are few clinical studies investigating the pharmacological interaction and abuse liability of their combined use, this hypothesis has not been extensively evaluated in clinical settings. As such, our analysis encourages further systematic investigation of BZD abuse among opioid abusers. The co-abuse of BZDs and opioids is substantial and has negative consequences for general health, overdose lethality, and treatment outcome. Physicians should address this important and underappreciated problem with more cautious prescribing practices, and increased vigilance for abusive patterns of use.

Pain response in heroin users: personality, abstinence, and modulation by benzodiazepines

We compared cold-pain responses among male current opioid users with and without concurrent benzodiazepine use, long-term ex-users, and healthy controls. Forty-eight current opioid users (14 concurrently using benzodiazepines), 34 ex-users (abstinent for ≥1 y) and 63 controls received cold-pressor tests. Pain threshold (first reporting pain) and pain tolerance (total immersion time) were recorded. Pain thresholds were similar in ex-users and current users; pain tolerance was similar in ex-users and controls. Net pain tolerance (endurance) in ex-users was intermediate between the other two groups. Current users showed higher pain threshold and shorter pain tolerance than controls (p<0.05). Current users not co-using benzodiazepines showed the lowest pain tolerance and net pain tolerance, and differed significantly from controls, ex-users, and current users co-using benzodiazepines (p<0.05). Neuroticism was higher in current users than in the other two groups (p<0.001), extraversion marginally lower (p<0.05); net pain tolerance differences remained significant after controlling for these. Benzodiazepine use modulates pain tolerance in opioid users. Pain responses altered by opioid use may partially recover with abstinence.

Pediatric End-of-Life Issues and Palliative Care

Optimizing the quality of medical care at the end of life has achieved national status as an important health care goal. Palliative care, a comprehensive approach to treating the physical, psychosocial and spiritual needs of patients and their families facing life-limiting illnesses, requires the coordinated efforts of a multidisciplinary group of caregivers. Understanding the basic principles of palliative care can aid emergency department staff in identifying patients who could benefit from palliative care services and in managing the challenging situations that arise when such patients present to the hospital for care.In this article we present the overall philosophy of pediatric palliative care, describe key elements of quality palliative care, and identify additional referral sources readers can access for more information.

Withdrawal symptoms in children after long-term administration of sedatives and/or analgesics: a literature review. "Assessment remains troublesome"

BACKGROUND

Prolonged administration of benzodiazepines and/or opioids to children in a pediatric intensive care unit (PICU) may induce physiological dependence and withdrawal symptoms.

OBJECTIVE

We reviewed the literature for relevant contributions on the nature of these withdrawal symptoms and on availability of valid scoring systems to assess the extent of symptoms.

METHODS

The databases PubMed, CINAHL, and Psychinfo (1980-June 2006) were searched using relevant key terms.

RESULTS

Symptoms of benzodiazepine and opioid withdrawal can be classified in two groups: central nervous system effects and autonomic dysfunction. However, symptoms of the two types show a large overlap for benzodiazepine and opioid withdrawal. Symptoms of gastrointestinal dysfunction in the PICU population have been described for opioid withdrawal only. Six assessment tools for withdrawal symptoms are used in children. Four of these have been validated for neonates only. Two instruments are available to specifically determine withdrawal symptoms in the PICU: the Sedation Withdrawal Score (SWS) and the Opioid Benzodiazepine Withdrawal Scale (OBWS). The OBWS is the only available assessment tool with prospective validation; however, the sensitivity is low.

CONCLUSIONS

Withdrawal symptoms for benzodiazepines and opioids largely overlap. A sufficiently sensitive instrument for assessing withdrawal symptoms in PICU patients needs to be developed.

Evaluation of the antinociceptive effect of Rosmarinus officinalis L. using three different experimental models in rodents

The rationale of this investigation was to examine the antinociceptive effect of an ethanol extract of Rosmarinus officinalis (RO) aerial parts, using three different experimental models: acetic acid-induced writhing test and formalin test in mice; and a model of arthritic pain: "pain-induced functional impairment model in the rat (PIFIR model)". The antinociceptive efficacies were evaluated using several dose-response curves and time courses. The antinociceptive effects from RO extract were compared with the antinociceptive effect of either tramadol (TR: 3.16-50 mg/kg, i.p. in mice, and 1.0-31.62 mg/kg, i.p. in rats) or acetylsalicylic acid (AA: 31.62-562.32 mg/kg, p.o.). RO extract (10-300 mg/kg, p.o.) significantly (P < 0.001) reduced the number of writhing movement induced by the i.p. administration of acetic acid solution in a dose-dependent way (ED50 = 108.84 mg/kg, whereas, TR showed an ED50 = 12.38 mg/kg). In addition, RO extract (30-300 mg/kg) significantly (P < 0.001) inhibited licking and shaking behaviours in both early (neurogenic pain) and in the late (inflammatory pain) phases of the formalin test. These effects were like those produced by TR. Concerning the results using the PIFIR model, RO extract (30-3000 mg/kg, p.o.) like either TR or AA, produced a significant (P < 0.001) and dose-dependent antinociceptive response in rats (RO: ED50 = 222.78 mg/kg versus TR: ED50 = 11.06 mg/kg and AA: ED50 = 206.13 mg/kg). These results strongly suggest that aerial parts of RO possess antinociceptive and anti-inflammatory activity, and reinforce the use of this plant in folk medicine.

A prospective evaluation of opioid weaning in opioid-dependent pediatric critical care patients

Critically ill children are treated with opioid medication in an attempt to decrease stress and alleviate pain during prolonged pediatric intensive care. This treatment plan places children at risk for opioid dependency. Once dependent, children need to be weaned or risk development of a withdrawal syndrome on abrupt cessation of medication. We enrolled opioid-dependent children into a prospective, randomized trial of 5- versus 10-day opioid weaning using oral methadone. Children exposed to opioids for an average of 3 wk showed no difference in the number of agitation events requiring opioid rescue (3 consecutive neonatal abstinence scores >8 every 2 h) in either wean group. Most of the events requiring rescue occurred on day 5 and 6 of the wean in both treatment groups. Patients may be able to be weaned successfully in 5 days once converted to oral methadone, with a follow-up period after medication wean to observe for a delayed withdrawal syndrome.

Tolerance and Withdrawal Issues with Sedation

The stay in an ICU is a complex mixture of providing optimal care while keeping the patient safe. Means of reducing the anxiety associated with the ICU stay include frequent reorientation and maintenance of patient comfort with sedation supplemented by analgesia as needed. The most common agents used to provide sedation include benzodiazepines, propofol, and the newer dexmedetomidine. Others include barbiturate agents, neuroleptics, clonidine, etomidate, ketamine, and supplemental opioid analgesics for pain control. A common complication of sedation is tolerance, which can lead to withdrawal if the sedation is discontinued hastily. This article evaluates the occurrence of tolerance and withdrawal in the most commonly used sedatives in critically ill patients.

Methadone dosage for prevention of opioid withdrawal in children

BACKGROUND

Opioids are frequently used for sedation in the Paediatric Intensive Care Unit (PICU). With time the dosing often increases because of tolerance. On cessation of the sedation there is a risk of the opioid withdrawal syndrome. The aim of our study was to evaluate methadone dosing as a risk factor for opioid withdrawal and to determine optimal dose and efficacy of methadone to prevent withdrawal.

METHOD

We undertook a clinical, retrospective, chart review study. Data were analysed from the quality improvement initiative database of a tertiary-care 18 bed PICU.

RESULTS

Data from 30 children who received an opioid infusion for >/=7 days and subsequently received methadone for opioid withdrawal (between January 2000 and July 2001) were analysed. Nurses documented the presence or absence of withdrawal signs daily. Our unit protocol has recommended converting the patient's opioid dose into fentanyl equivalents and a dose of methadone equal to the total daily dose of fentanyl to be given three times a day. Twenty patients had no or minimal withdrawal symptoms and 10 experienced significant withdrawal. Age, weight, PRISM score, lorazepam dose, muscle relaxant use and fentanyl dose were not statistically significantly between these groups. Receiver Operator Characteristics analysis showed that 80% of the suggested methadone dose was effective in minimizing withdrawal symptoms. The odds ratio for withdrawal with <80% of the predicted methadone dose was 21.

CONCLUSIONS

Inadequate methadone is a risk factor for opioid withdrawal. A daily starting methadone dose equivalent to 2.5 times the daily fentanyl dose is effective in minimizing withdrawal symptoms.

Effect ofRosmarinus of?cinalis L. aerial parts extract on morphine withdrawal syndrome in mice

The effect the aqueous and ethanol extracts of Rosmarinus officinalis L. aerial parts on morphine withdrawal syndrome was investigated in mice. The aqueous and ethanol extracts induced a significant antinociceptive activity in the writhing test. This activity was inhibited by naloxone pretreatment. Dependence was induced using subcutaneous injections of morphine daily for 3 days. On day 4, morphine was injected 2 h prior to the intraperitoneal injection of naloxone. The number of jumps during the 30 min period after naloxone injection was considered as a measure of the withdrawal syndrome. The results indicated that the aqueous (1.68 g/kg and 2.4 g/kg, i.p.) and ethanol (0.96 g/kg, i.p.) extracts reduced the number of jumps. Phytochemical study indicated that only the aqueous extract of R. officinalis has an alkaloid component. It is concluded that the aqueous and ethanol extracts of R. officinalis aerial parts could diminish morphine withdrawal syndrome.

Practices and Predictors of Analgesic Interventions for Adults Undergoing Painful Procedures

• Background Research is limited on analgesic practices associated with the commonly performed procedures of turning, inserting central venous catheters, removing wound drains, changing dressings on nonburn wounds, suctioning the trachea, and removing femoral sheaths.

• Objective To determine types of analgesics administered for procedures, the prevalence and amounts of drugs given, and factors predictive of analgesic administration.

• Methods Pain was assessed before and immediately after procedures. Analgesic, sedative, and anesthetic agents administered within 1 hour before and/or during each procedure were noted.

• Results A total of 5957 adult patients at 164 national and 5 international sites participated. Pain intensity increased at the time of procedure for all procedures. More than 63% of patients received no analgesics. Less than 20% received opiates; mean total dose of opiate was 6.44 mg (SD, 8.96 mg). Only 10% of patients received combination therapy. Factors associated with the likelihood of receiving opiates were pain intensity before a procedure, femoral sheath removal, being white, and the duration of a procedure. Patients less likely to receive opiates had a medical diagnosis or were having tracheal suctioning. Only 14.5% of the variance in the amount of opiate administered was explained by factors entered into multiple regression models. Type of procedure was the only significant predictor of amount of opiate administered.

• Conclusions Most patients were not intentionally medicated even though pain intensity increased during their procedure. When used, analgesic amounts were low, and combination therapy was infrequent. Clinical trials are needed to evaluate optimal pain management for patients undergoing procedures.

When midazolam fails

Significant distress is experienced by patients, families, and caregivers when a symptom or disorder, such as an agitated delirium, becomes an intractable, or a catastrophic event, such as irreversible stridor. When palliative sedation is indicated for these patients, midazolam is usually the preferred drug. In some cases, however, midazolam fails to provide adequate sedation. Two cases are presented to illustrate this phenomenon and explore the possible mechanisms underlying this lack of response. These mechanisms appear to be multifaceted. The heterogeneity of the GABA(A) receptor complex and the alterations that this complex can undergo functionally can explain, to some degree, the diversity of the physiological and pharmacological outcomes. Other factors responsible for the diversity in response may include concomitant medications, age, concurrent disease, overall health status, alcohol use, liver disease, renal disease, smoking and hormonal status. Evidence-based guidelines on alternative treatment options should midazolam fail are required. In the interim, a lower threshold for adding an alternative drug, such as phenobarbital, or substituting midazolam with another drug, such as propofol, should be considered in these circumstances.

Ventilation of patients with asthma and chronic obstructive pulmonary disease

Ventilatory intervention is often life-saving when patients with asthma or chronic obstructive pulmonary disease (COPD) experience acute respiratory compromise. Although both noninvasive and invasive ventilation methods may be viable initial choices, which is better depends upon the severity of illness, the rapidity of response, coexisting disease, and capacity of the medical environment. In addition, noninvasive ventilation often relieves dyspnea and hypoxemia in patients with stable severe COPD. On the basis of current evidence, the general principles of ventilatory management common to patients with acutely exacerbated asthma/COPD are these: noninvasive ventilation is suitable for a relatively simple condition, but invasive ventilation is usually required in patients with more complex or more severe disease. It is crucial to provide controlled hypoventilation, longer expiratory time, and titrated extrinsic positive end-expiratory pressure to avoid dynamic hyperinflation and its attendant consequences. Controlled sedation helps achieve synchrony of triggering, power, and breath timing between patient and ventilator. When feasible, noninvasive ventilation often facilitates the weaning of ventilator-dependent patients with COPD and shortens the patient's stay in the intensive care unit.

Effects of Ferula gummosa Boiss. fractions on morphine dependence in mice

Activity-guided fractionation of methanol-chloroform (1:1) extract of Ferula gummosa was carried out to investigate the isolation of the active component(s) responsible for the alleviation of morphine withdrawal syndrome induced by naloxone. Dependence was induced using subcutaneous (s.c.) injections of morphine daily for three days. On day 4, morphine was injected 0.5 h before the interaperitoneal (i.p.) injections of fractions or diazepam (5 mg/kg, i.p.) as positive control. Naloxone was injected (5 mg/kg, s.c.) 2 h after the final dose of morphine. The number of episodes of jumping during 30 min after the injection of naloxone was considered as the intensity of the withdrawal syndrome. The methanol-chloroform (1:1) extract of the aerial parts of plant was prepared and partitioned between water and chloroform. The active chloroform layer was concentrated and partitioned between methanol-water (9:1) and n-hexane. Activity was observed in the hydroalcoholic layer. This layer was concentrated and partitioned further between methanol-water (3:2) and chloroform. The chloroform layer showed a dose-dependent and significant activity. For all fractions the activity was observed at 470 mg/kg. Further purification on silica gel column chromatography gave a pure compound, which was 10 times as effective as the crude extract. The results of this study indicated that the plant extract contained component(s) that could be useful for the alleviation of morphine withdrawal syndrome.

Effect of Salvia leriifolia leaf extract on morphine dependence in mice

The effect of Salvia leriifolia leaf extract on morphine dependence was investigated in mice. Dependence was induced using subcutaneous injections of morphine daily for 3 days. On day 4, morphine was injected 2 h before the intraperitoneal injection of naloxone. The number of episodes of jumping during the 30 min after injection of naloxone was considered as the intensity of the withdrawal syndrome. The ethanol extract reduced the number of jumping episodes dose-dependently. The extract at a dose of 500 mg/kg was as effective as a dose of 5 mg/kg of diazepam in reducing the number of jumping episodes. The effect of the extract was blocked by aminophylline (20 mg/kg), a non-selective antagonist of adenosine receptors. It is concluded that the ethanol extract of S. leriifolia leaves could diminish the withdrawal syndrome of morphine.

Iatrogenic drug dependence--a problem in intensive care? Case study and literature review

Use of sedative and analgesic pharmacological agents is a widespread practice in intensive care units (ICUs). Mainly, this involves opioid and benzodiazepine analogues, both known to induce dependence/tolerance states. This paper is based on a clinical scenario in which a patient treated with these agents developed problems when they had been discontinued, and exploration of the extent of such problems generally. The problems range across a wide range of domains and may include physical discomfort, difficulty weaning from respiratory assistance and the drugs, and the problems of short- and long-term psychological distress. Although there may be a recognition that these drugs can typically cause dependence problems, little emphasis has traditionally been given to assessing these problems in ICUs. Yet the ICU may be an area where these drugs are used in high volumes. The recognition, physiology, management and prevention of iatrogenic drug dependence/tolerance in critical care environments is elucidated, with reference to relevant literature.